sedimentary
Sandstone Moqui Marble (Concretion)
Iron oxide concretion (Hematite/Goethite and Quartz)
AI-generated identification · may be incorrectHardness: 5.0-6.0 on Mohs scale; Color: Dark brown to rusty black exterior; Luster: Dull, earthy, or metallic; Structure: Spherical or ellipsoidal with a sandstone core; Specific Gravity: Approx 3.0-4.0.
- Hardness
- 5
- Color
- Dark brown to rusty black exterior
- Luster
- Dull, earthy, or metallic
Identified More sedimentary →
Explore Sandstone Moqui Marble (Concretion) in the encyclopedia →Identify your own rocks.
Get a report just like this from any photo, free.
Physical properties
Hardness: 5.0-6.0 on Mohs scale; Color: Dark brown to rusty black exterior; Luster: Dull, earthy, or metallic; Structure: Spherical or ellipsoidal with a sandstone core; Specific Gravity: Approx 3.0-4.0.
Formation & geological history
Formed in the Jurassic Navajo Sandstone roughly 130 to 180 million years ago. These concretions result from the precipitation of iron-rich minerals from groundwater flowing through porous sandstone, often forming around a nucleus.
Uses & applications
Primarily collected as geological specimens due to their unique shapes. In metaphysical circles, they are used as 'shaman stones.' Historically, they had no major industrial use but are significant for studying groundwater flow.
Geological facts
Legend has it that the spirits of the Hopi ancestors would play games with these 'marbles' at night. They are also being studied by NASA because similar 'blueberries' were found on Mars, suggesting past water activity.
Field identification & locations
Identify by the distinct spherical shape, dark iron-rich crust, and a lighter sandstone interior if broken. Often found in the American Southwest, particularly in Utah. Collectors should look for them weathering out of sandstone cliffs.
More like this
Other sedimentary specimens
Fossiliferous Sedimentary Rock
Sedimentary limestone with invertebrate fossil imprint
fossil
Sandstone or Siltstone
Arenite (if sandstone)
Sedimentary
Sandstone
Arenite
sedimentary
Quartz pebble
Silicon dioxide (SiO2)
sedimentary
Generic Pebble / Rock Fragment
Lithic fragment / Weathered rock
sedimentary
Shale
Shale (clastic sedimentary rock)
sedimentary